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.� Work Plan for Refined Plume Definition and Management of Floating Product-7500 WIN St., Tracy, CA. Page 35 9.0 PROGRAM FOR MANAGEMENT OF FLOATING PRODUCT Light non-aqueous phase liquid (LNAPL) or "floating product" was first removed from the surface of the groundwater beneath the 7500 West Eleventh Street site at the time the underground fuel storage tanks and appurtenances were exhumed (see Section 2.3 above). Interim measures to remove floating product from Monitoring Well MW-7, located across West Eleventh Street to the north of the property, were initiated on November 8, 2003 (see Section 2.4 above). The elements of the LNAPL-management program completed to date are summarized below, together with descriptions of three technologies that might be applied to complete removal of LNAPL present on the plume of affected groundwater. SJC's recommendation with respect to the appropriate technology for the site-specific conditions is also presented. ■- 9.1 Floating Product Managed During Tank Removal As was described in Section 2.3, 2,000 gallons of floating product were removed from Tank -- Pit No. 1 in December 1998 at the time that tanks located there were removed. However, the floating product did not originate at that location. None of the underground storage tanks that had been located there had leaked (Dietz Irrigation 1999a). Floating product flowed into Tank Pit No. I some several hours after it had been excavated from an area to the west, beneath the pump island at the former fueling station. See Figures 2 and 3 for locations. The floating product that flowed into Tank Pit No. 1 was skimmed from the water surface using a vacuum truck and shipped off site for disposal at a permitted facility. After further delay, floating product again accumulated in the tank pit. That LNAPL was also removed " from the subsurface by drawing it into a vacuum truck for off-site disposal and after a few such cycles, the groundwater cleared and remained free of floating fuel hydrocarbons. As was also discussed in Section 2.3, that procedure was effective in removing all floating product from the area beneath the 7500 West Eleventh Street property itself and creating conditions that permitted analytes of concern to decrease as measured by the groundwater- quality monitoring program that has been conducted since that time. 9.2 Interim Measures to Manage Floating Product in Area of Monitoring Well MW-7 In response to the SJCEHD directive to initiate immediately removal of floating product in the vicinity of Monitoring Well MW-7 (San Joaquin County Environmental Health Department 2003), SJC initiated weekly pumping of floating product from that well on November 8, 2003. 9.2.1 Procedure_for Measurement of the Thickness of Floating Product On each occasion, prior to initiating pumping of LNAPL from the well, the thickness of product floating on the groundwater in the well is measured. This is done by coating the sic